Image Resizer Online Free
Resize images by exact pixel dimensions or percentage. Lock aspect ratio to prevent distortion, choose output format, and download the result instantly. No upload to any server — runs entirely in your browser.
Drop an image here or click to browse
JPEG, PNG, WebP, GIF, BMP
How to Resize an Image
- 1Drop your image onto the upload area or click to browse for a file (JPEG, PNG, WebP, GIF, BMP).
- 2Choose By Dimensions to enter exact pixel sizes, or By Percentage to scale proportionally.
- 3Select an output format and quality level, then click Resize Image.
- 4Click Download to save the resized image to your device.
When to Use Each Output Format
JPEG is the best choice for photographs — it offers small file sizes with adjustable quality. PNG is lossless and supports transparency, making it ideal for logos, icons, and screenshots. WebP is a modern format that offers better compression than JPEG at equivalent quality and is supported by all modern browsers.
Image Resizing Tips
Common Social Media Sizes
Twitter profile: 400×400px. Instagram post: 1080×1080px. Facebook cover: 820×312px. LinkedIn profile: 400×400px. Use the dimensions mode for exact targets.
Retina Display
For screens with 2x pixel density (Retina, HiDPI), create images at 2x the display size. A 200×200 display image should be 400×400px in the source file.
Web Performance
Serving images at their displayed size rather than relying on CSS to scale them down significantly improves page load speed. Use the percentage mode to scale by 50% for a quick optimization.
JPEG Quality
For web use, JPEG quality of 75–85% typically offers a good balance between file size and visual quality. Quality above 90% gives diminishing returns with much larger file sizes.
Frequently Asked Questions
Does resizing an image reduce quality?
Upscaling (making an image larger than the original) always reduces quality since it requires inventing pixel data that does not exist. Downscaling generally preserves quality well. For JPEG output, higher quality settings (80–95%) minimize compression artifacts.
Is my image uploaded to a server?
No. The entire resizing process happens in your browser using the HTML5 Canvas API. Your image never leaves your device.
What formats can I output?
You can output JPEG (with adjustable quality), PNG (lossless), or WebP (modern format with excellent compression). JPEG is best for photographs; PNG for graphics with transparency; WebP for web delivery where browser support allows.
What does "lock aspect ratio" do?
When enabled, changing the width automatically adjusts the height proportionally (and vice versa) so the image is not distorted. Disable it to set arbitrary dimensions that may stretch the image.
What is the maximum image size?
The browser's Canvas API can handle very large images, but performance depends on available memory. For images over 20 megapixels, you may experience slower processing. The tool works best with images up to about 4000×4000 pixels.